Torsional vibration damper



April 9, 1957 R. A. JUMISCO 2,787,896

TORSIONAL VIBRATION DAMPER Filed Dec. 18, 1955 2 heets-sheet 1 INVENTOR I y figg/vCge/Z msco "qy BY $09M- ATI'OIRNEY April 9, 1957 R. A. Jumlscd 2,787,896

'I'ORSIONAL VIBRATION DAMPER.

Filed Dec. 18, 1953 2 Sheets-Sheet 2 I IIQVENTOR .Qgy Q e/zz'zzzisco BY ATTORNEY United States Patent 6 TORSION AL DAMPERi Roy A. Jumisco, Detroit, Mich.,.assignor: to General Motors Corporation, Detroit," Mich}, a corporation of Delaware ApplicationDecember 18, 1953; Serial No.-398,'966.

6 Claims; (CI: 64-27) This invention: relates ger-rerally:to1machinesf-which:em ploy frictionally engaging .drivermembersaand: in particular to a device adaptable for use .withirrsuch:m'achinesfor preventing backlash :or play betweenfsuclrdriveimembers;

In machines; driven: by gear tooth'edgsplinedfi or" other similar: drive members and normallyrhaving intermittent periodsxof operation, considerable difiiculty-isexperienced in providing a' constant driving 'force free'i ofltheadverse effects ofxbacklash or play betweent suchmembers; Al-i though such: drive means 1 are; designed; with; minimum tolerancesv between the frictionally" engagin'gydrivesmem-x bers continual use causes gradual 'wear upon :theen'gaging surfaces. Such wear increasesthetolerance;betweenithe drive members, magnifies the 'backlash-"ortplay permissible and consequently increases'thetratezof wear and depreciation;

An example of a. structurelhaving these ditficulties'." is the gear hobbing machine. The gear hob or cutting memher which is secured to adr'iven' shaffintermittently engages a work piece and consequently'subjects the driving members to constantly reversing torsional forces. When the. gear hob is driven by spline. connected drive means, asis quite conventional, there are also. space limitations which heretofore have prevented employing any of f the known damping or anti-backlash devices. Thus it is readily seen that the nature of the drive employed, particular characteristics of the machine, and the available space within which to incorporate corrective devices all have an influence upon whether or not such devices may be used.

It is now proposed to provide a device which may be readily associated with a gear hobbing machine or other structure to insure a constant driving force between frictionally engaging drive members and to provide for steady engagement between such drive members free of the effects of backlash, play, and the like. The device is adapted to act between the drive members without being secured therebetween. This is accomplished by providing a secondary drive which is disposed apart from the primary drive but is associated with the same driven member. By spring loading the secondary drive, which may be secured at any position along the driven member and near the drive member where space permits, the primary rive is constantly urged in firm engagement with the driven member and backlash or play is prevented. The proposed device may be secured to the ends of parallel drive shafts as shown in the present adaptation of the device and may therefore be added to machines already in operation with a minimum of effort or skill. The device is inexpensive to manufacture, easily attached or removed, and highly eflicient in operation.

Figure l is a cross sectional side elevational view of a part of a gear hobbing machine.

Figure 2 is a side elevational view partially in cross section showing the proposed device adapted for association with a gear hobbing machine. Figure 2 is taken in the plane of line 2-2 of Figure 3 viewed in the direction of the arrows thereon.

Patented Apr. 9, 1957 Figure;:3:israafrontwievwof theiproposed device aszta-ken in the plane of line 33 of Figure 2.

. EiguresSw. is a fragmentary sectionediview through one ofzthestorqueiapplicator means in thezplanei of: 3a--3a of Figure-.3: takenrin the direction ofszthearrowsrzthereon:

Figurei4 is-qan exploded view of a segmental portionrof the: device showninxFigure 3.

The gear. hobbing machine; ltlrshowrr in :thedrawings includes. av casingr or'housing 12.; A .worm gear? 14-. is

adapted. to drive aehelical' gearr16 which: is secured ito a.

tubular; shaft-.181 The tubular shaftiS is ijournalled inlthe sleevei hearirigvZO; A'wflywheel. 22 is secured near the outer end of the tubular shaft 18. Aspindle: 24iis disposed centrally within the tubular shaft 183.. andi is splined:theretoiassatlo: At draw barz28- extends; through thetzspindlei 24 and .is: securedito the hob arbor 3th The outerzendrofithe draw barr28 is: formed with: a hexagonal head .32 tonenableiidrawingthe bar-and thelhobwarborriitl into: secure engagement withfthespindle 24 disposedithere between; Th'ef'liobiarbonfihhs .journalled within bearings 34zand: 36.:and;isiadapteditozhave a gear hob. 38 keyed thereto; Thepworkipieceetkishown'in phantom; is. disposed: on :a 1carri'err42': for:horizonta'llrotational movement and is adapted to be engaged by the cutting teeth a t of the'i gearthob7361- Thus the-driving force transmit-tedibetween:gears;14=-and:.lfi isrconveyed: through: the spiined drive 26t0f Etheitubular shaft 18' toJthe spindle 24 land? the geanhohzarborfiilr A? torsional .vibrationidarnper or .secondaryxdrive device- 46' is secured: torthe'iends of the tubular:shaftilSr-andfthe spindle 24. The end of the spindle 24 is threadedasatfld toreceive-aisplinedlsleevel5t); The draw bar-'23 extends through itheisp'lined?v sleeve 50 as'throughf the spindle: 24: A collar '52riis-formed on the draw bar '28: and is disposed withinI-thesplined sleevedtl to abut against a" shoulder 54 formedwithin.thetsleeve. Ahardenedsteel washer 56 'isdisposed betweenthe shoulder 5'4 and .theacollarzSZ; The outer-end ofthetubularshaftlitais also threadeda as at? 585: and. adapted. to 1 receives. an annular: retainer plate 602' having a: flange: 62 formed cir'cumferentiall y'theree around and extending rearwardly away from the flywheel 22.

In mesh with the spline ways 64 of the sleet e 54 is drive plate 66. Annular disks 68 and 79 are disposed on opposite sides of the drive member 66 and are circumferentially secured to the flange 62 of the retainer plate 60 as by bolts or other fastening means 72. The disks 68 and 70 are arranged in spaced relation to the drive plate 66 with their inner peripheral edges riding against friction disks 74 secured on opposite sides of the drive plate. In the present embodiment only the one disk 79 need be cupped as at 76 to accommodate the drive plate 66 between the disks.

A plurality of circumferentially spaced openings 78, Bil, and 82 are formed through the drive plate 66 and the annular disks 68 and 79 respectively for receiving coil springs 84. Lips or fingers 36 are formed from the disks 68 and 70 and are projected within the openings 80 and 82 by the lips 86 and 88 as shown in Figures 2 and 3. With the dampener device 46 assembled and secured in position for operation the retain plate 60 may be finally balanced as by lighting holes 9% formed within the edge of the plate.

The drive plate 66 is rotated slightly relative to the disks 68 and 70 to compress the springs 84 between the leading edge 92 of the drive plate opening 78 and the trailing edges 94 and 96 of the disk openings 89 and 82, as best seen in Figure So, before the disks 68 and 71B are secured to the retainer plate 6%. The secondary drive device 46 thus provides a spring loaded driving force for rotating the spindle 24. Since the primary driving force is transmitted through the spline connected tubular shaft 18 and spindle 24 the torsional load imposed by the secondary drive device 46 assists in overcoming any reverse movement within the splined connection 26 and thereby prevents backlash within the primary drive spline connection.

The driving force through the worm and helical gears 14 and 16 remains constant at all times. The intermittent reverse torsional forces caused by the disengagement of the hob cutter teeth 44 from the work piece 40 are absorbed or damped out within the coil springs 84. The driving spline connections 26 and 64 are protected by the absorption of such forces Within the coil springs 84. The spring loading may be varied by altering the relative positions of the drive plate 66 to the disks 68 and 70 to assure the elimination of all effects of backlash within the drive connections.

I claim:

1. Torque applicator means for use with machines having drive members spline connected to driven members, and which includes parallel spaced disk members having a plate member disposed therebetwecn, means securing a plate member disposed in spaced relation therebetween the outer periphery of said disks together and to a drive member, means securing said plate to said driven member,

and means coacting between said disk and plate members for continuously biasing said drive member through said plate in anti-backlashing drive engagement with said driven member.

2. Torque applicator means as provided for by claim 1 which includes otfset apertures formed through said disk and plate members and having disposed therein said biasing means which includes a spring member under compression and having one end thereof engaging said disks only and the other end thereof engaging only said plate member.

3. In combination with splined drive means, a torque applicator device for biasing the drive member of said drive means in engagement with the driven member thereof, said device including parallel spaced disk members having a plate member disposed therebetween, means securing the outer periphery of said disks together and to said drive member, means securing said plate to said driven member, and means coacting between said disk and plate members for continuously biasing said drive and secured to one of said driving means, said disk memers having their outer peripheries secured together and to the other of said driving means, and means coacting between said disk and plate members for continuously biasing said driving means in drive engagement.

6. In combination with a gear hobbing machine having spline connected gear hob driving means, a shaft extension provided upon the end of a driven member of said driving means, parallel spaced annular disk members secured together at their outer periphery and to a drive member of said driving means, said shaft extension being received centrally through said disk members, an annular plate member connected to said shaft extension and disposed in parallel spaced relation between said disk members, offset apertures formed within said disk and References Cited in the file of this patent UNITED STATES PATENTS 1,727,153 Ahlene Sept. 3, 1929 1,830,746 Ahlene et al Nov. 10, 1931 2,042,570 Wemp June 2, 1936 2,176,696 Wemp Oct. 17, 1939 2,521,138 Waller Sept. 5, 1950 

